Electronic apparatus, position specifying system, position specifying method, and storage medium

ABSTRACT

An electronic apparatus includes a processor and a memory. The processor executes a program stored in the memory to perform operations including: acquiring a series of position information of a user; detecting whether or not a loss part, in which position information corresponding to a predetermined time or a predetermined number of times of measurement is lost, is present in the series of position information acquired; and specifying the detected loss part in a case where the loss part is detected.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based on and claims the benefit of priority fromJapanese Patent Application No. 2017-063846 filed on Mar. 28, 2017, thecontent of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to an electronic apparatus, a positionspecifying system, a position specifying method, and a storage medium.

Related Art

Conventionally, there is a technique of not displaying GPS positioningpositions having low positioning accuracy when a moving trajectory of auser is displayed. Such a technique, for example, is disclosed inJapanese Patent-Laid-Open No. 2014-29281.

However, there are cases in which an error occurs in positioninformation after GPS position information could not be acquired for apredetermined period. In Patent Document 1 described above, an erroroccurring in such position information is not considered, anddetermination of appropriateness/inappropriateness of the positioninformation of a user cannot be performed with high accuracy.

The present invention is in consideration of such situations, and anobject thereof is to perform determination ofappropriateness/inappropriateness of the position information of a userwith higher accuracy.

According to the present invention, determination ofappropriateness/inappropriateness of position information of a user canbe performed with higher accuracy.

SUMMARY OF THE INVENTION

An electronic apparatus according to an aspect of the present inventionincludes a processor and a memory. The processor executes a programstored in the memory to perform operations including: acquiring a seriesof position information of a user; detecting whether or not a loss part,in which position information corresponding to a predetermined time or apredetermined number of times of measurement is lost, is present in theseries of position information acquired; and specifying the detectedloss part in a case where the loss part is detected.

A position specifying system according to an aspect of the presentinvention includes: a first electronic apparatus that includes aprocessor and a memory; and a second electronic apparatus that includesa processor and a memory. In at least one of the first electronicapparatus and the second electronic apparatus, the processor executes aprogram stored in the memory to perform operations including: acquiringa series of position information of a user; detecting whether or not aloss part, in which position information corresponding to apredetermined time or a predetermined number of times of measurement islost, is present in the series of position information acquired; andspecifying the detected loss part in a case where the loss part isdetected.

A position specifying method executed by an electronic apparatusaccording to an aspect of the present invention includes a processor.The position specifying method causes the processor to execute a programstored in a memory to perform operations including: acquiring a seriesof position information of a user; detecting whether or not a loss part,in which position information corresponding to a predetermined time or apredetermined number of times of measurement is lost, is present in theseries of position information acquired; and specifying the detectedloss part in a case where the loss part is detected.

A non-transitory computer-readable storage medium according to an aspectof the present invention stores a program that is executable by acomputer that comprises a processor. The program is executable to causethe computer to perform operations including: acquiring a series ofposition information of a user; detecting whether or not a loss part, inwhich position information corresponding to a predetermined time or apredetermined number of times of measurement is lost, is present in theseries of position information acquired; and specifying the detectedloss part in a case where the loss part is detected.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is an external configuration diagram of a wrist terminal as aportable terminal according to one embodiment of the present invention.

FIG. 1B is a block diagram that illustrates the hardware configurationof a wrist terminal as a portable terminal according to one embodimentof the present invention.

FIG. 2 is a functional block diagram that illustrates the functionalconfiguration for performing a position specifying process and aparameter control process among functional configurations of the wristterminal illustrated in FIG. 1B.

FIG. 3A is a schematic diagram that illustrates parameters used in anacceleration filter.

FIG. 3B is a schematic diagram that illustrates parameters used in aloss extension filter.

FIG. 3C is a schematic diagram that illustrates parameters used in apositioning context filter.

FIG. 4 is a schematic diagram that illustrates a relation between thetype of behavior and a used filter.

FIG. 5 is a diagram that schematically illustrates the characteristicsof an acceleration filter.

FIG. 6 is a diagram that schematically illustrates the characteristicsof a loss extension filter.

FIG. 7 is a diagram that schematically illustrates the characteristicsof a positioning context filter.

FIG. 8 is a flowchart that describes the flow of a position specifyingprocess performed by the wrist terminal illustrated in FIG. 1B havingthe functional configuration illustrated in FIG. 2.

FIG. 9 is a flowchart that describes the flow of an acceleration filterprocess.

FIG. 10 is a flowchart that illustrates the flow of a loss extensionfilter process.

FIG. 11 is a flowchart that describes the flow of a positioning contextfilter process.

FIG. 12 is a schematic diagram that illustrates an example in which auser's position is displayed using history data (history data that hasnot been processed) before a filter process using a position specifyingprocess is performed.

FIG. 13 is a schematic diagram that illustrates an example in which auser's position is displayed using history data after a filter processusing a position specifying process is performed.

FIG. 14 is a flowchart that describes the flow of a parameter controlprocess performed by the wrist terminal illustrated in FIG. 1B havingthe functional configuration illustrated in FIG. 2.

FIG. 15 is a functional block diagram that illustrates the functionalconfiguration of a wrist terminal for performing a submergence detectionfilter process.

FIG. 16 is a flowchart that describes the flow of a submergencedetection filter process.

DETAILED DESCRIPTION OF THE INVENTION

Embodiments of the present invention will be explained with reference tothe drawings.

FIGS. 1A and 1B are diagrams illustrating the configuration of a wristterminal 1 as an embodiment of an information terminal according to thepresent invention. FIG. 1A is a view illustrating an outer appearance ofthe wrist terminal 1. FIG. 1B is a block diagram illustrating a hardwareconfiguration of the wrist terminal 1. The wrist terminal 1 is anapparatus that is configured to be of wristwatch type and has functionssimilar to a smart phone. As illustrated in FIG. 1B, the wrist terminal1 includes a control unit 11, a sensor unit 12, an input unit 13, an LCD(Liquid Crystal Display) 14, a timepiece circuit 15, ROM (Read OnlyMemory) 16, RAM (Read Access Memory) 17, a GPS antenna 18, a GPS module19, a wireless communication antenna 20, a wireless communication module21, and a drive 22. Where appropriate, the wrist terminal 1 can includedifferent hardware such as an imaging unit.

The control unit 11 is configured with an arithmetic processing unitsuch as a CPU (Central Processing Unit) serving as a processor andcontrols the overall operation of the wrist terminal 1. For example, thecontrol unit 11 executes various types of processing according to aprogram such as a program for position specifying process (describedlater) stored in the ROM 16. The sensor unit 12 includes various typesof sensors such as an acceleration sensor, a gyroscope sensor, abarometer, a magnetic field sensor, or an altitude sensor. Theacceleration sensor detects an acceleration in three axis directions ofthe wrist terminal 1, and outputs information indicating the detectedacceleration to the control unit 11. The gyroscope sensor detects anangular velocity in three axis directions of the wrist terminal 1, andoutputs information indicating the detected angular velocity to thecontrol unit 11. The barometer detects the atmospheric pressure ofenvironment where the wrist terminal 1 is present, and outputsinformation indicating the detected atmospheric pressure to the controlunit 11. Based on the information output from the barometer, the wristterminal 1 detects the altitude of the wrist terminal 1.

The input unit 13 is configured with various buttons or capacitive-typeor resistance-film-type position input sensors laminated on a displayarea of the LCD 14, and inputs various types of information according toa user's operation for instruction. The LCD 14 outputs an imageaccording to an instruction of the control unit 11. For example, the LCD14 displays various images and screens of a user interface. In thepresent embodiment, a position input sensor of the input unit 13 isarranged so as to be superimposed on the LCD 14 to constitute a touchscreen. The timepiece circuit 15 generates a time signal from signalsgenerated by a system clock or oscillator to output the current time.

The ROM 16 stores information such as control programs executed by thecontrol unit 11. The RAM 17 provides a work area used by the controlunit 11 to execute various types of processing. The GPS antenna 18receives radio waves sent from satellites for GPS, converts them intoelectrical signals, and outputs the electrical signals thus converted(hereinafter, referred to as “GPS signal”) to the GPS module 19. The GPSmodule 19 detects the location (latitude, longitude, and altitude) ofthe wrist terminal 1 and the current time shown by the GPS based on theGPS signals input from the GPS antenna 18. The GPS module 19 outputsinformation showing the location thus detected and the current time tothe control unit 11.

The wireless communication antenna 20 is an antenna that can receiveradio waves of frequencies corresponding to wireless communication usedby the wireless communication module 21 and is configured with a loopantenna and a rod antenna, for example. The wireless communicationantenna 20 sends electrical signals of wireless communication inputtedfrom the wireless communication module 21 as electromagnetic waves,converts the electromagnetic waves thus received into electricalsignals, and outputs them to the wireless communication module 21. Thewireless communication module 21 sends signals to another apparatus viathe wireless communication antenna 20 in accordance with an instructionfrom the control unit 11. Furthermore, the wireless communication module21 receives signals sent from another apparatus and outputs informationindicated by the signals thus received to the control unit 11. Aremovable medium 31 composed of a magnetic disk, an optical disk, amagneto-optical disk, semiconductor memory or the like is loaded to thedrive 22 as necessary. The removable medium 31 can store a variety ofdata such as the image data.

FIG. 2 is a functional block diagram that illustrates the functionalconfiguration for performing a position specifying process and aparameter control process among functional configurations of the wristterminal 1 illustrated in FIG. 1B. A position specifying process is aseries of processes in which a position is specified by applying variousfilters (an acceleration filter, a loss extension filter, and apositioning context filter) to be described later to information of aposition acquired by a GPS module (hereinafter, referred to as“positioning information” as is appropriate) to suppress use ofinappropriate information. In addition, a parameter control process is aseries of processes in which whether or not a position specified byperforming a filter process with parameters set in a position specifyingprocess is appropriate is verified as an ex post facto, and theparameters are updated with more appropriate values in accordance with aresult of the verification. In a case in which the position specifyingprocess and the parameter control process are performed, as illustratedin FIG. 2, in a control unit 11, a positioning information acquiringunit 51, a behavior determining unit 52, a filter selecting unit 53, afirst filter processing unit 54, a second filter processing unit 55, athird filter processing unit 56, a parameter control unit 57, and adisplay control unit 58 function. In addition, in one area of a ROM 16,a history data storage unit 71, a parameter storage unit 72, and a mapinformation storage unit 73 are set. In the history data storage unit71, history data of positioning results is stored for each behavior of auser (for every behaviors corresponding to one day, one activity, or thelike). In addition, as the history data, both unprocessed data that isdata in which original information of a position acquired by the GPSmodule is stored and history data of positions specified from results ofapplying various filters to be described later are stored. The parameterstorage unit 72 stores parameters used in various filters to bedescribed later.

FIGS. 3A to 3C are schematic diagrams illustrating one example ofparameters used in various filters. FIG. 3A is a diagram thatillustrates parameters used in an acceleration filter, FIG. 3B is adiagram that illustrates parameters used in a loss extension filter, andFIG. 3C is a diagram that illustrates parameters used in a positioningcontext filter. In FIGS. 3A to 3C, set numerical values are representedwith appropriate omission. As illustrated in FIG. 3A, in theacceleration filter, as types of activity, “trekking”, “fishing”,“cycling”, “paddle” (paddling in a kayak or the like), “surfing”, and“snow” (ski, snowboard, or the like) are defined, and, for these, aconverted speed value Va [km/s] and a time interval criterion Sa [s] areset. The converted speed value Va represents a threshold of the degreeof increase (acceleration) in the speed between two points a and b in atime series of the history data. The time interval criterion Sa is athreshold set using an experimental value or an experience value and, avalue to be applied is set for each activity.

In addition, as illustrated in FIG. 3B, in the loss extension filter, astypes of activity, “daily behavior”, “trekking”, “fishing”, “cycling”,“paddle” (paddling in a kayak or the like), “surfing”, and “snow” (ski,snowboard, or the like) are defined, and, for these, a loss threshold Seand a loss extension ratio X [%] are set. The loss threshold Se is athreshold used for determining whether or not a loss extension filter isto be applied. The loss extension ratio X represents a ratio at which aloss period (time) is extended.

In addition, as illustrated in FIG. 3C, in the positioning contextfilter, as types of activity, “daily behavior”, “trekking”, “fishing”,“cycling”, “paddle” (paddling in a kayak or the like), and “snow” (ski,snowboard, or the like) are defined, and, for these, a return radius Rn[m], a converted speed value Vd [km/h], and a time interval criterion hd[h] are set as thresholds. The return radius Rn represents a thresholdof a distance between a point a that is a time point before a point b ofinterest and a point c that is a time point after the point b in threepoints a, b, and c of history data in a time series. The converted speedvalue Vd represents a threshold of L/h1, wherein a time interval betweenthe point a and the point b is h1, and a distance between the point band the point a is L. The time interval criterion hd is a threshold setusing an experimental value or an experience value and, here, athreshold Tth1 that is common to the activities is set. Referring backto FIG. 2, in the map information storage unit 73, map information usedfor displaying a position specified by a position specifying process inan overlapping manner is stored.

The positioning information acquiring unit 51 acquires information of aposition (positioning information) acquired by the GPS module at apredetermined interval (for example, an interval of 0.1 seconds). Then,the positioning information acquiring unit 51 stores the acquiredpositioning information in the history data storage unit 71 as historydata. The behavior determining unit 52 determines (selects) the type ofbehavior performed by a user using the wrist terminal 1. At this time,the behavior determining unit 52 can determine a behavior by determiningthe behavior from information (a type of activity that is directlydesignated or a type of activity that is indirectly perceived from anoperation of a navigation system or the like) representing the type ofbehavior input by the user or analyzing the positioning information or ameasurement result acquired by the sensor unit 12. In addition, the typeof behavior may be determined by analyzing a user's behavior patternusing the behavior determining unit 52.

The filter selecting unit 53 selects a filter to be used among theacceleration filter, the loss extension filter, and the positioningcontext filter and parameters to be used in the used filter inaccordance with the type of behavior determined by the behaviordetermining unit 52. In this embodiment, a filter to be used is set inadvance in accordance with the type of behavior. Each filter, forexample, is realized by a program executing a filter process andfunctions as a determination device determiningappropriateness/inappropriateness of the positioning information.

FIG. 4 is a schematic diagram that illustrates a relation between thetype of behavior and a used filter. As illustrated in FIG. 4, one of theacceleration filter, the loss extension filter, and the positioningcontext filter to be used for each type of behavior is set in advance.In this embodiment, the order of filters of an applied case is set to bethe order of the acceleration filter, the loss extension filter, and thepositioning context filter in accordance with the characteristics of thefilters. As an example, in a case where a user's behavior is determinedto be cycling, the acceleration filter, the loss extension filter, andthe positioning context filter are applied in the mentioned order.

In a case in which the acceleration filter is determined to be used bythe filter selecting unit 53, the first filter processing unit 54performs a filter process using the acceleration filter by using theparameters selected by the filter selecting unit 53. The accelerationfilter is a filter that excludes positioning information exceeding anacceleration that is not possible in a real world as an abnormal value(determines the positioning information as an invalid value and excludesthe value) on the basis of the acceleration acquired from thepositioning information. In addition, the positioning informationexcluded by the acceleration filter is not handled as a loss of data,and data before and after the exclusion is handled as adjacent data.

FIG. 5 is a diagram that schematically illustrates the characteristicsof the acceleration filter. As illustrated in FIG. 5, for example, inthe case of riding a bicycle, in a case where the acceleration in atraveling direction exceeds a human's acceleration limit (in animpossible case), the acceleration can be estimated as an abnormalvalue.

In the acceleration filter, when a GPS reception environment is good,positioning information that is an exclusion target is limited. Thus,the acceleration filter has an effect that is gentler than the otherfilters and is a filter mainly using past data and thus is a filterhaving high immediacy. For this reason, in this embodiment, theacceleration filter is set as an initial filter for positioninginformation. In a case in which the loss extension filter is determinedto be used by the filter selecting unit 53, the second filter processingunit 55 performs a filter process using the loss extension filter byusing the parameters selected by the filter selecting unit 53. The lossextension filter is a filter that, in a case where a relatively longpositioning loss period is generated, masks a positioning result for apredetermined time also after the end of the actual loss period (apositioning result after a predetermined loss period is determined asbeing an invalid value and is excluded), thereby suppressing apositioning disturbance occurring immediately after the loss period. Inother words, the loss extension filter determines theappropriateness/inappropriateness of positioning information inaccordance with the acquisition status (the length of the loss period)of the positioning information.

FIG. 6 is a diagram that schematically illustrates the characteristicsof the loss extension filter. As illustrated in FIG. 6, in a case wherea loss period exceeding a threshold is generated in the GPS positioninginformation, a loss extension period acquired by extending the lossperiod at a predetermined ratio is set, and positioning informationafter the elapse of the loss extension period is maintained as historydata after the filter process. In other words, in this embodiment, theloss extension period is set to be changed in accordance with the lengthof the loss period, and, as the loss period becomes longer, the lossextension period is set to be longer. According to this configuration, aproblem in that, as the loss period becomes longer, a positioning errorin position information acquired after the loss period increases, and ittakes time to acquire correct position information can be solved. Inaddition, it may be configured such that a constant loss extensionperiod is set regardless of the length of the loss period. By using aconstant loss extension period, the amount of processing required forthe determination of appropriateness/inappropriateness of the positioninformation can be decreased. In addition, the loss extension filter canset positioning information that is not appropriate for display to be ina non-display state through simple calculation and thus is an effectivefilter for an electronic device performing a power-saving processperforming positioning using only positioning information of a GPSwithout performing positioning according to self-contained navigation.Since the loss extension filter excludes positioning information over arelatively long period, there are cases in which it is not appropriatefrom the viewpoint of likelihood for the evaluation of positioninginformation to apply the acceleration filter to data after a filterprocess using the loss extension filter. For this reason, the lossextension filter is set as a filter of a stage later than that of theacceleration filter.

In a case in which the positioning context filter is determined to beused by the filter selecting unit 53, the third filter processing unit56 performs a filter process using the positioning context filter byusing the parameters selected by the filter selecting unit 53. Thepositioning context filter is a filter that excludes jumps of suddenpositioning results occurring regardless of the situations on the basisof user's behavior tendency (determines jumps of sudden positioningresults as invalid values and excludes such jumps).

FIG. 7 is a diagram that schematically illustrates the characteristicsof the positioning context filter. As illustrated in FIG. 7, in a casewhere a round-trip over a radius of action, which is set on the basis ofuser's behavior tendency, is performed in a short time, it cannot be auser's behavior and thus can be estimated as an abnormal value. In theexample illustrated in FIG. 7, a user's radius of action is set usingpositioning information of points a and c that are time points beforeand after positioning information of a point b of interest in a timeseries, and it is determined whether or not the positioning informationof the point b is an abnormal value with respect to the radius ofaction. By using the positioning information of the points a and c thatare time points before and after the time point b in the time series fordetermining whether or not the positioning information of the point b isan abnormal value, compared to a case in which only the positioninginformation of a time point before the positioning information ofinterest, even in a case where a behavior state and a moving speedgreatly change before and after the point of interest, determination ofan abnormal value can be performed with high accuracy. The process isnot limited to the process described above, and it may be configuredsuch that a user's radius of action is set by using only the positioninginformation of the point c that is a time point after the positioninginformation of the point b in the time series, and it is determinedwhether or not the positioning information of the point b is an abnormalvalue. The positioning context filter can adaptively exclude variouserrors that cannot be eliminated by the acceleration filter and the lossextension filter and thus is set as a filter of a final stage.

By performing a parameter control process, the parameter control unit 57detects an error from an actual position in a result of specifying aposition through a position specifying process and feeds the error backsto the values of the parameters used in each filter. Accordingly,machine learning of the parameters used in the position specifyingprocess is performed, and the parameters having high accuracy can beachieved. For example, the parameter control unit 57, for training datain which the actual position is known in advance, specifies a positionthrough the position specifying process from positioning informationacquired by the positioning information acquiring unit and adjusts theparameters of the filter such that a difference between the specifiedposition and a position of a correct answer is decreased. Other than acase in which training data in which the actual position is known inadvance is used, in a case where a position having a predetermined levelof validity is estimated through map matching (route fitting) or thelike, the parameters of the filter may be adjusted such that adifference between the estimation result and a position specified by theposition specifying process is decreased.

The parameter control process is performed as an ex post facto processfor the position specifying process at a timing (for example, midnight)at which the operating rate of the control unit 11 of the wrist terminal1 is low. Here, when the position specifying process is performed, byperforming the parameter control process in parallel therewith, theparameter control unit 57 may sequentially update the parameters. Thedisplay control unit 58 displays a map screen on which a positionrepresenting a moving history is displayed to be superimposed on mapinformation on an LCD 14 on the basis of the history data after thefilter process that is stored in the history data storage unit 71. Therecording control unit 59 stores process results of the first filterprocessing unit 54, the second filter processing unit 55, and the thirdfilter processing unit 56 in the history data storage unit 71. Inaddition, the recording control unit 59 stores a result of the filterprocess in the history data storage unit 71 in association withunprocessed data with the unprocessed data, in which sensor informationacquired by the sensor unit 12 or the information of a position acquiredby the GPS module is stored in its original state, maintained.

[Operation]

Next, the operation of the wrist terminal 1 will be described.

[Positioning Process]

FIG. 8 is a flowchart that describes the flow of a position specifyingprocess performed by the wrist terminal 1 illustrated in FIG. 1B havingthe functional configuration illustrated in FIG. 2. The positionspecifying process is started by a user's direction for starting theposition specifying process.

In step S1, information of a position acquired by the GPS module(positioning information) is acquired at a predetermined interval (forexample, at the interval of 0.1 seconds). In step S2, the positioninginformation acquiring unit 51 stores the acquired positioninginformation in the history data storage unit 71 as history data. In stepS3, the behavior determining unit 52 determines the type of behaviorperformed by the user using the wrist terminal 1.

In step S4, the filter selecting unit 53 determines whether or not thetype of behavior determined by the behavior determining unit 52 is atarget behavior for using the acceleration filter. In a case in whichthe type of behavior determined by the behavior determining unit 52 is atarget behavior for using the acceleration filter, “Yes” is determinedin step S4, and the process proceeds to step S5. On the other hand, in acase where the type of behavior determined by the behavior determiningunit 52 is not a target behavior for using the acceleration filter, “No”is determined in step S4, and the process proceeds to step S7.

In step S5, the filter selecting unit 53 selects parameters to be usedby the acceleration filter on the basis of the type of behaviordetermined by the behavior determining unit 52. In step S6, the firstfilter processing unit 54 performs a filter process (acceleration filterprocess) using the acceleration filter by using the parameters selectedby the filter selecting unit 53.

In step S7, the filter selecting unit 53 determines whether or not thetype of behavior determined by the behavior determining unit 52 is atarget behavior for using the loss extension filter. In a case in whichthe type of behavior determined by the behavior determining unit 52 is atarget behavior for using the loss extension filter, “Yes” is determinedin step S7, and the process proceeds to step S8. On the other hand, in acase where the type of behavior determined by the behavior determiningunit 52 is not a target behavior for using the loss extension filter,“No” is determined in step S7, and the process proceeds to step S10.

In step S8, the filter selecting unit 53 selects parameters to be usedby the loss extension filter on the basis of the type of behaviordetermined by the behavior determining unit 52. In step S9, the secondfilter processing unit 55 performs a filter process (loss extensionfilter process) using the loss extension filter by using the parametersselected by the filter selecting unit 53.

In step S10, the filter selecting unit 53 determines whether or not thetype of behavior determined by the behavior determining unit 52 is atarget behavior for using the positioning context filter. In a case inwhich the type of behavior determined by the behavior determining unit52 is a target behavior for using the positioning context filter, “Yes”is determined in step S10, and the process proceeds to step S11. On theother hand, in a case where the type of behavior determined by thebehavior determining unit 52 is not a target behavior for using thepositioning context filter, “No” is determined in step S10, and theprocess proceeds to step S13.

In step S11, the filter selecting unit 53 selects parameters to be usedby the positioning context filter on the basis of the type of behaviordetermined by the behavior determining unit 52. In step S12, the thirdfilter processing unit 56 performs a filter process (positioning contextfilter process) using the positioning context filter by using theparameters selected by the filter selecting unit 53. In step S13, therecording control unit 59 stores a result of the filter process in thehistory data storage unit 71.

In step S14, the display control unit 58 displays a map screen, in whicha position representing a moving history is displayed to be superimposedon map information, on the LCD 14 on the basis of the history data afterthe filter process that is stored in the history data storage unit 71.After step S14, until an operation directing the end of the positionspecifying process is performed by the user, the position specifyingprocess is repeated.

[Acceleration Filter Process]

Next, the acceleration filter process performed in step S6 of theposition specifying process will be described. FIG. 9 is a flowchartthat describes the flow of the acceleration filter process. In step S21,the first filter processing unit 54 acquires positioning information oftwo points a and b in a time series that are processing targets.

In step S22, the first filter processing unit 54 determines whether ornot the speed of the point b is a first threshold or less. The firstthreshold is a value of low speed (for example, 2 km/h) for which thespeed at the point b can be estimated to be substantially zero. In acase in which the speed of the point b is the first threshold or less,“Yes” is determined in step S22, and the process proceeds to step S23.On the other hand, in a case where the speed of the point b is not thefirst threshold or less, “No” is determined in step S22, and the processproceeds to step S24.

In step S23, the first filter processing unit 54 sets the speed of thepoint b to zero. After step S23, the positioning information that is theprocessing target is transitioned to the next two points, and theprocess proceeds to step S21. In step S24, the first filter processingunit 54 determines whether or not a time interval between the points aand b is the time interval criterion Sa or more. In a case in which thetime interval between the points a and b is not the time intervalcriterion Sa or more, “No” is determined in step S24, and the processproceeds to step S25. On the other hand, in a case where the timeinterval between the points a and b is the time interval criterion Sa ormore, “Yes” is determined in step S24, and the process proceeds to stepS26.

In step S25, the first filter processing unit 54 calculates a convertedspeed difference V as the converted speed difference V=(the speed of thepointb−the speed of the point a)/S. In step S26, the first filterprocessing unit 54 calculates the converted speed difference V as theconverted speed difference V=(the speed of the pointb−0)/S. In otherwords, in step S26, in a case where a positioning loss is continued fora long time, the degree of increase in the speed (acceleration) of thepoint b is evaluated through a comparison with zero.

In step S27, the first filter processing unit 54 determines whether ornot the converted speed difference V is a converted speed value Va ormore. The process of step S27 corresponds to determination of whether ornot the positioning information of the point b is an invalid value fromthe viewpoint of the acceleration. In a case in which the convertedspeed difference V is not the converted speed value Va or more, “No” isdetermined in step S27, and the process proceeds to step S21. On theother hand, in a case where the converted speed difference V is theconverted speed value Va or more, “Yes” is determined in step S27, andthe process proceeds to step S28.

In step S28, the first filter processing unit 54 deletes the point bfrom the history data as an abnormal value. In step S29, the firstfilter processing unit 54 determines whether or not a condition forreturning to the position specifying process is satisfied. The conditionfor returning to the position specifying process, for example, in a casewhere the history data stored in the history data storage unit 71 isprocessed as an ex post facto, is being final data of the processingtarget (being at the end of data in units of activity, corresponding toone day, or the like) and, in a case where positioning information isprocessed in real time, when each block of data temporarily stored in abuffer having a predetermined size is processed, being final data of theprocessing target (being at the end of a block of data stored in thebuffer), or the like. In addition, in a case where the positioninginformation is processed in real time and in a case where data is notstored in a buffer (the process is performed every time when positioninginformation is input), in step S29, the condition for returning to theposition specifying process is determined to be satisfied. In a case inwhich the condition for returning to the position specifying process isnot satisfied, “No” is determined in step S29, and the positioninginformation of the processing target is transitioned to the next twopoints, and the process proceeds to step S21. On the other hand, in acase where the condition for returning to the position specifyingprocess is satisfied, “Yes” is determined in step S29, and the processis returned to the position specifying process.

[Loss Extension Filter Process]

Next, the loss extension filter process performed in step S9 of theposition specifying process will be described. FIG. 10 is a flowchartthat illustrates the flow of the loss extension filter process. In stepS41, the second filter processing unit 55 acquires one piece ofpositioning information. Here, the positioning information is acquiredat a predetermined interval (for example, at the interval of 0.1 secondsor the like) and, in step S41, a process of sequentially acquiringpositioning information to be acquired at the predetermined interval foreach one loop is performed.

In step S42, the second filter processing unit 55 determines whether ornot a loss occurs in the acquisition of the positioning information. Ina case in which a loss does not occur in the acquisition of thepositioning information, “No” is determined in step S42, and the processproceeds to step S43. On the other hand, in a case where a loss occursin the acquisition of the positioning information, “Yes” is determinedin step S42, and the process proceeds to step S44.

In step S43, the second filter processing unit 55 stores the acquiredpositioning information as history data, and the process proceeds tostep S50. In step S44, the second filter processing unit 55 counts up aloss period of the positioning information.

In step S45, the second filter processing unit 55 determines whether ornot the loss period has ended. In a case in which the loss period hasnot ended, “No” is determined in step S45, and the process proceeds tostep S44. On the other hand, in a case where the loss period has ended,“Yes” is determined in step S45, and the process proceeds to step S46.

In step S46, the second filter processing unit 55 determines whether ornot the length S of the loss period is a loss threshold Se or more. Theprocess of step S46 corresponds to determination of a positioning resultafter a constant loss period as being an invalid value. In a case inwhich the length S of the loss period is not the loss threshold Se ormore, “No” is determined in step S46, and the process proceeds to stepS50. On the other hand, in a case where the length S of the loss periodis the loss threshold Se or more, “Yes” is determined in step S46, andthe process proceeds to step S47. In step S47, the second filterprocessing unit 55 sets a loss extension period (=loss period×lossextension rate X).

In step S48, the second filter processing unit 55 determines whether ornot the loss extension period has elapsed. In a case in which the lossextension period has not elapsed, “No” is determined in step S48, andthe process proceeds to step S49. On the other hand, in a case where theloss extension period has elapsed, “Yes” is determined in step S48, andthe process proceeds to step S50.

In step S49, the second filter processing unit 55 deletes thepositioning information acquired in the loss extension period from thehistory data, transitions the positioning information of the processingtarget to a next point, and the process is returned to step S48. In stepS50, the second filter processing unit 55 determines whether or not thecondition for returning to the position specifying process is satisfied.The condition for returning to the position specifying process, forexample, in a case where the history data stored in the history datastorage unit 71 is processed as an ex post facto, is being final data ofthe processing target (being at the end of data in units of activity,corresponding to one day, or the like) and, in a case where positioninginformation is processed in real time, when each block of datatemporarily stored in a buffer having a predetermined size is processed,being final data of the processing target (being at the end of a blockof data stored in the buffer), or the like. In addition, in a case wherethe positioning information is processed in real time and in a casewhere data is not stored in a buffer (the process is performed everytime when positioning information is input), in step S50, the conditionfor returning to the position specifying process is determined to besatisfied. In a case in which the condition for returning to theposition specifying process is not satisfied, “No” is determined in stepS50, and the positioning information of the processing target istransitioned to the next point, and the process proceeds to step S41. Onthe other hand, in a case where the condition for returning to theposition specifying process is satisfied, “Yes” is determined in stepS50, and the process is returned to the position specifying process.

[Positioning Context Filter Process]

Next, the positioning context filter process performed in step S12 ofthe position specifying process will be described. FIG. 11 is aflowchart that describes the flow of the positioning context filterprocess. In step S61, the third filter processing unit 56 acquireslongitude and latitude and positioning time of each of three points a,b, and c in a time series that are processing targets. In step S62, thethird filter processing unit 56 calculates a time interval h1 betweenthe points a and b and a time interval h2 between the points b and c.

In step S63, the third filter processing unit 56 determines whether thetime interval h1 between the points a and b is the time intervalcriterion hd or more or whether the time interval h2 between the pointsb and c is the time interval criterion hd or more. In step S63, in acase where the time interval h1 between the points a and b is the timeinterval criterion hd or more, or the time interval h2 between thepoints b and c is the time interval criterion hd or more, “Yes” isdetermined in step S63, and the process proceeds to step S70. On theother hand, in step S63, in a case where the time interval h1 betweenthe points a and b is not the time interval criterion hd or more, andthe time interval h2 between the points b and c is not the time intervalcriterion hd or more, “No” is determined in step S63, and the processproceeds to step S64.

In step S64, the third filter processing unit 56 calculates a returndistance R (a distance between the points a and c acquired from thelongitude and latitude). In step S65, the third filter processing unit56 determines whether or not the return distance R is the return radiusRn or less. In a case in which the return distance R is not the returnradius Rn or less, “No” is determined in step S65, and the processproceeds to step S70. On the other hand, in a case where the returndistance R is the return radius Rn or less, “Yes” is determined in stepS65, and the process proceeds to step S66.

In step S66, the third filter processing unit 56 calculates an adjacencydistance L between the points a and b (a distance between the points aand b acquired from the longitude and latitude). In step S67, the thirdfilter processing unit 56 calculates an adjacency converted speed Vm(=L/h1). In addition, at this time, as the adjacency converted speed Vm,although a speed at the time of moving from the point a to the point bis configured to be calculated, a moving speed at the time of movingfrom the point b to the point c may be configured to be calculated andbe used for determination. In step S68, the third filter processing unit56 determines whether or not the converted speed value Vd is theadjacency converted speed Vm or less. The process of step S68corresponds to determination of a sudden jump of a positioning result asbeing an invalid value. In a case in which the converted speed value Vdis not the adjacency converted speed Vm or less, “No” is determined instep S68, and the process proceeds to step S70. On the other hand, in acase where the converted speed value Vd is the adjacency converted speedVm or less, “Yes” is determined in step S68, and the process proceeds tostep S69.

In step S69, the third filter processing unit 56 deletes the point bfrom the history data as an abnormal value. In other words, inaccordance with the determinations of steps S63 and S68, in the case of“returning to a nearby position” “at a high speed”, the point b isdeleted from the history data. In step S70, the third filter processingunit 56 determines whether or not the condition for returning to theposition specifying process is satisfied. The condition for returning tothe position specifying process, for example, in a case where thehistory data stored in the history data storage unit 71 is processed asan ex post facto, is being final data of the processing target (being atthe end of data in units of activity, corresponding to one day, or thelike) and, in a case where positioning information is processed in realtime, when each block of data temporarily stored in a buffer having apredetermined size is processed, being final data of the processingtarget (being at the end of a block of data stored in the buffer), orthe like. In addition, in a case where the positioning information isprocessed in real time and in a case where data is not stored in abuffer (the process is performed every time when positioning informationis input), in step S70, the condition for returning to the positionspecifying process is determined to be satisfied. In a case in which thecondition for returning to the position specifying process is notsatisfied, “No” is determined in step S70, and the positioninginformation of the processing target is transitioned to the next threepoints, and the process proceeds to step S61. On the other hand, in acase where the condition for returning to the position specifyingprocess is satisfied, “Yes” is determined in step S70, and the processis returned to the position specifying process.

By using such a process, an abnormal value in the positioninginformation of a GPS can be appropriately excluded, and a more correctposition can be specified. FIG. 12 is a schematic diagram thatillustrates an example in which a user's position is displayed usinghistory data (history data that has not been processed) before a filterprocess using a position specifying process is performed. In the exampleillustrated in FIG. 12, history data including errors such as anabnormal value of acceleration, incorrect position information acquiredafter a loss period, and moving that is not possible as a user'sbehavior is displayed.

FIG. 13 is a schematic diagram that illustrates an example in which auser's position is displayed using history data after the filter processusing the position specifying process is performed. In the exampleillustrated in FIG. 13, history data limited to more correct data isdisplayed which is acquired by appropriately excluding errors such as anabnormal value of acceleration, incorrect position information acquiredafter a loss period, and moving that is not possible as a user'sbehavior using the acceleration filter, the loss extension filter, andthe positioning context filter. In addition, the process of excluding anabnormal value in the positioning information can be performed byreferring to the history data stored in the history data storage unit 71in a situation in which the supply of power to the wrist terminal 1 issufficiently performed (during charging or the like) or in a situationin which the processing load is distributed in time, and positioning isnot performed.

[Parameter Control Process]

Next, a parameter control process will be described. FIG. 14 is aflowchart that describes the flow of the parameter control processperformed by the wrist terminal 1 illustrated in FIG. 1B having thefunctional configuration illustrated in FIG. 2. The parameter controlprocess is started when an operation for directing the start of theparameter control process is performed by a user.

In step S81, the parameter control unit 57 acquires data referred to asa correct answer in the parameter control process. Here, the datareferred to as a correct answer, for example, is training data in whichthe actual position is known in advance or data of which a positionhaving a constant degree of validity is estimated through map matching(route fitting) or the like. In step S82, the parameter control unit 57acquires history data after the filter process using the positionspecifying process.

In step S83, the parameter control unit 57 calculates an error betweenthe data referred to as the correct answer and the history data afterthe filter process. In step S84, the parameter control unit 57 feeds thecalculated error back and adjusts parameters of each filter. In stepS85, the parameter control unit 57 stores the parameters after theadjustment in the parameter storage unit 72.

In step S86, the parameter control unit 57 performs a positionspecifying process of unprocessed data stored in the history datastorage unit 71 by using the parameters after the adjustment in eachfilter. After step S86, the parameter control process ends. In this way,by using more appropriate parameters that have been adjusted, theposition specifying process can be restarted, and accordingly, a moreaccurate position can be specified.

Modified Example 1

In the embodiment described above, in addition to the accelerationfilter process, the loss extension filter process, and the positioningcontext filter process, a submergence detection filter process detectingthe submergence of the wrist terminal 1 may be performed. FIG. 15 is afunctional block diagram that illustrates the functional configurationof the wrist terminal 1 for performing the submergence detection filterprocess.

The submergence detection filter process is a series of processes inwhich, in a case where a user's behavior is surfing or paddle, it isdetected whether or not the wrist terminal 1 is submerged, andpositioning information during submergence is deleted from the historydata. In a case in which the submergence detection filter is performed,a fourth filter processing unit 60 functions in addition to thefunctional configuration illustrated in FIG. 2. The fourth filterprocessing unit 60 performs a filter process using the submergencedetection filter by using parameters selected by the filter selectingunit 53 in a case where the submergence detection filter is determinedto be used by the filter selecting unit 53.

The submergence detection filter is a filter detecting that the wristterminal 1 is submerged by using that the altitude represents anabnormal value before and after a loss period in a case where the wristterminal 1 is submerged, and positioning information is lost. FIG. 16 isa flowchart that describes the flow of the submergence detection filterprocess. The submergence detection filter process is performed as afilter process of a final stage in a case where a user's behavior isdetermined to be surfing or paddle in a position specifying process. Instep S91, the fourth filter processing unit 60 acquires positioninginformation.

In step S92, the fourth filter processing unit 60 determines whether ornot the initial value A0 of the altitude is in a set state. In a case inwhich the initial value A0 of the altitude is not in the set state, “No”is determined in step S92, and the process proceeds to step S93. On theother hand, in a case where the initial value A0 of the altitude is inthe set state, “Yes” is determined in step S92, and the process proceedsto step S95.

In step S93, the fourth filter processing unit 60 determines whether ornot a predetermined number (here, five) of pieces of positioninginformation have been acquired after the start of the positioning. In acase in which the predetermined number of pieces of positioninginformation have not been acquired after the start of the positioning,“No” is determined in step S93, and the process proceeds to step S91. Onthe other hand, in a case where the predetermined number of pieces ofpositioning information have been acquired after the start of thepositioning, “Yes” is determined in step S93, and the process proceedsto step S94.

In step S94, the fourth filter processing unit 60 sets the initial valueA0 of the altitude that is a criterion. In a case in which the standarddeviation of the predetermined number of pieces of positioninginformation is 15 [m] or more, the initial value A0 of the altitude isset as an average value of the altitudes of the predetermined number ofpieces of positioning information excluding a maximum value and aminimum value. On the other hand, in a case where the standard deviationof the predetermined number of pieces of positioning information is lessthan 15 [m], the initial value A0 of the altitude is set as an averagevalue of the altitudes of the predetermined number of pieces ofpositioning information. After step S94, the process proceeds to stepS91.

In step S95, the fourth filter processing unit 60 calculates an averageof altitudes of a predetermined number (here, five) of pieces ofpositioning information that have been acquired latest as a currentaltitude An. In step S96, the fourth filter processing unit 60determines whether or not a difference between the current altitude Anand the initial value A0 of the altitude is an altitude differencethreshold (for example, 40 [m]) or more. In a case in which thedifference between the current altitude An and the initial value A0 ofthe altitude is the altitude difference threshold or more, “Yes” isdetermined in step S96, and the process proceeds to step S97. On theother hand, in a case where the difference between the current altitudeAn and the initial value A0 of the altitude is not the altitudedifference threshold or more, “No” is determined in step S96, and theprocess proceeds to step S98.

In step S97, since the current altitude An is an abnormal value, thefourth filter processing unit 60 deletes the current positioninginformation from the history data. In step S98, the fourth filterprocessing unit 60 determines whether or not a condition for returningto the position specifying process is satisfied. The condition forreturning to the position specifying process, for example, in a casewhere the history data stored in the history data storage unit 71 isprocessed as an ex post facto, is being final data of the processingtarget (being at the end of data in units of activity, corresponding toone day, or the like) and, in a case where positioning information isprocessed in real time, when each block of data temporarily stored in abuffer having a predetermined size is processed, being final data of theprocessing target (being at the end of a block of data stored in thebuffer), or the like. In addition, in a case where the positioninginformation is processed in real time and in a case where data is notstored in a buffer (the process is performed every time when positioninginformation is input), in step S98, the condition for returning to theposition specifying process is determined to be satisfied. In a case inwhich the condition for returning to the position specifying process isnot satisfied, “No” is determined in step S98, and the process proceedsto step S91. On the other hand, in the case of the final data of theprocessing target, “Yes” is determined in step S98, and the process isreturned to the position specifying process. In this way, a positioningdisturbance occurring after the submergence period can be suppressed.

Modified Example 2

In the embodiment described above, in a case where the parameters areupdated by the parameter control unit, the position specifying processmay be performed again to specify a more appropriate position. Forexample, in activities performed on one day, history data of a positionspecified in the position specifying process may be stored asprovisional history data. Then, by performing a parameter controlprocess at a timing such as midnight and performing a positionspecifying process using the updated parameters, the position in theactivities of the day can be updated with a more appropriate position.This series of the parameter control process and the position specifyingprocess may be performed by a server that has uploaded the history datafrom the wrist terminal 1 or the like.

Modified Example 3

In the embodiment described above, in a case where the result ofspecifying a position is desired to be displayed in real time, not aresult of application of all the filters but one of stages of a resultof the process of the acceleration filter, a result of the process ofthe loss extension filter, and a result of the process of thepositioning context filter may be selected and displayed in accordancewith a display mode.

Modified Example 4

In the embodiment described above, although a case in which the numberof pieces of positioning information that are determination targets forthe positioning context filter is two has been described as an example,the present invention is not limited thereto. In other words, the numberof pieces of positioning information that are determination targets forthe positioning context filter may be increased (for example, eight). Ina case in which the number of pieces of positioning information that aredetermination targets for the positioning context filter is two, displaycan be performed with a semi-real time characteristic (a sequentialcharacteristic suppressed to a short-time delay). Meanwhile, in a casewhere the number of pieces of positioning information that aredetermination targets for the positioning context filter is increased,the filter process can be performed as an ex post facto process with theaccuracy prioritized regardless of the real-time characteristic. In acase in which the number of pieces of positioning information that aredetermination targets for the positioning context filter is increased,for positioning information of interest, a radius of action and astatistical action range (adjacent action circle) are set using apredetermined number of pieces of positioning information before andafter the positioning information of interest (for example, respectivelyfour pieces of positioning information before and after the positioninginformation of interest) in the time series. For example, among thepredetermined number of sequential pieces of positioning information inthe time series, a longest distance thereof is set as a diameter, and anadjacent action circle having a half distance of this diameter as itsradius of action is set. Then, for this adjacent action circle, in acase where a round trip over the radius of action is performed in ashort time (for example, a round trip of a distance over three times theradius of action), it is impossible to perform such moving as a user'sbehavior, and the moving is estimated as an abnormal value. In addition,a selection ratio between pieces of position information, which aresequential in time, used for setting an adjacent circle of action may beadjusted in accordance with a display mode of the positioninginformation. Thus, in a case where position information sequentiallyacquired is stored in a buffer, and the position information isdisplayed in semi-real time, predetermined numbers of pieces ofpositioning information before and after the positioning information ofinterest, for example, may be configured to be selected at the ratio ofthree pieces of positioning information from time points before thepositioning information of interest in the time series and one piece ofpositioning information from a time point after the positioninginformation of interest. By configuring as such, display of a trajectoryhaving high accuracy can be performed almost in parallel with real-timeGPS positioning. In addition, the adjacent action circle may be setusing only position information acquired after the positioninginformation of interest as positioning information that is determinationtarget used for the process of determining the positioning informationof interest.

Modified Example 5

In the embodiment described above, the setting of the positioningcontext filter may be adaptively changed in accordance with variousconditions. For example, the number of pieces of positioning informationthat are determination targets for the positioning context filter may bechanged in accordance with user's various situations (the type ofbehavior, positioning environments, and the like) and various requests(a decrease in the amount of calculation and the like). For example, thenumber of pieces of positioning information that are determinationtargets for the positioning context filter may be increased or decreasedin accordance with user's cycling or daily behavior. In addition, thenumber of pieces of positioning information that are determinationtargets for the positioning context filter may be increased or decreasedin accordance with the residual amount of the battery or the processingload of the wrist terminal 1. Furthermore, in the embodiment describedabove, a method of selecting positioning information that is adetermination target for the positioning context filter may be changedin accordance with user' various situations (the type of behavior,positioning environments, and the like) and various requests (a decreasein the amount of calculation and the like). Here, the method ofselecting positioning information means position information before andafter positioning information of interest that is to be selected. Forexample, as a method of selecting positioning information, a method inwhich a predetermined number of pieces of positioning informationbefore/after the positioning information of interest are selected, amethod in which the number of pieces of positioning information afterthe positioning information of interest to be selected is more than thenumber of pieces of positioning information before the positioninginformation of interest, or, to the contrary, a method in which thenumber of pieces of positioning information before the positioninginformation of interest to be selected is more than the number of piecesof positioning information after the positioning information of interestmay be used. Also in such a case, for example, the method of selectingpositioning information that is a determination target for thepositioning context filter may be changed in accordance with user'scycling or daily behavior. In addition, the method of selectingpositioning information that is a determination target for thepositioning context filter may be changed in accordance with theresidual amount of the battery or the processing load of the wristterminal 1.

Modified Example 6

In the embodiment described above, although a case in which the presentinvention is applied to the positioning information of a GPS has beendescribed as an example, the present invention is not limited thereto.In other words, the present invention may be applied also to a case inwhich position information based on a network location is used togetherwith the positioning information of a GPS. For example, in a case wherea network location of a Wi-Fi router is used or the like, although asituation in which a positioning location is instantly transitioned to aforeign country and is returned may occur, also in such a situation, theeffects of the present invention can be acquired.

Modified Example 7

In the embodiment described above, map matching (route fitting) may beperformed by aggregating positioning information for the activities ofmany users in a server and setting a substantial route (virtual route)in map information in which a route has not been set. For example, avirtual route is set for a path of a lift in a sky resort, and mapmatching (route fitting) is performed, whereby the position can bespecified with higher accuracy. In addition, by performing a parametercontrol process using the information of the virtual route, theparameters of the filter can be adjusted.

The wrist terminal 1 configured as above includes a positioninginformation acquiring unit 51 and a second filter processing unit 55.The positioning information acquiring unit 51 acquires a series ofposition information of a user. The second filter processing unit 55detects whether or not a loss part in which position information is lostfor a predetermined time or a predetermined number of times ofmeasurement is present among the series of position information acquiredby the positioning information acquiring unit 51. In a case in which aloss part is detected, the second filter processing unit 55 specifiesthe loss part. In addition, in a case where a loss part is detected, thesecond filter processing unit 55 specifies the loss part and a partcorresponding to the predetermined time or the predetermined number oftimes of measurement from the loss part in the series of positioninformation as a part that is not appropriate for display. In this way,a disturbance in the positioning occurring immediately after the losspart can be suppressed. Accordingly, theappropriateness/inappropriateness of the position information of a usercan be determined with higher accuracy.

The wrist terminal 1 includes the recording control unit 59. Therecording control unit 59 outputs a series of pieces of positioninformation in which a part not appropriate for display is specified.Accordingly, a device other than the wrist terminal 1 can use a resultof the determination of appropriateness/inappropriateness of theposition information of a user.

The recording control unit 59 outputs data acquired by excluding a partthat is not appropriate for display from the series of positioninformation. In this way, only data that is appropriate as positioninformation of a user can be provided for a device other than the wristterminal 1.

The second filter processing unit 55 sets the length of a period, inwhich position information subsequent to a loss part is not output, tobe changeable. In this way, the period, in which position informationsubsequent to a loss part is not output, can be set to an appropriateperiod according to the situations.

As the length of a detected loss part is longer, the second filterprocessing unit 55 sets the length of the period, in which positioninformation subsequent to the loss part is not output, to be longer. Inthis way, in accordance with the magnitude of the influence of the losspart, the period, in which position information subsequent to the losspart is not output, can be set more appropriately.

In a case in which a detected loss part is a set threshold or more, thesecond filter processing unit 55 sets a period in which positioninformation subsequent to the loss part is not output. In this way, onlyin a case where the influence of a loss part substantially occurs, theperiod, in which position information subsequent to the loss part is notoutput, can be set.

The second filter processing unit 55 discards or invalidates positioninformation acquired by the positioning information acquiring unit 51 inthe period in which position information after a loss part is not outputand maintains position information acquired by the positioninginformation acquiring unit 51 after the period, in which positioninformation subsequent to the loss part is not output, elapses. In thisway, position information acquired in the period, in which positioninformation subsequent to the loss part is not output, is prevented frombeing output, and appropriate position information can be output afterthe elapse of the period in which position information subsequent to aloss part is not output.

The present invention is not limited to the embodiment described above,and changes, improvements, and the like in a range in which the objectof the present invention can be achieved belong to the presentinvention. For example, in the embodiment descried above, in a casewhere positioning information is deleted from the history data usingeach filter, data erasing, invalidation of data, or the like may beperformed. In addition, in the embodiment described above, in the lossextension filter, although a case in which the loss threshold Se is setfor each type of activity has been described as an example, this lossthreshold Se may be changed in accordance with the position or the time.Furthermore, in the embodiment described above, although thedetermination device determining the appropriateness/inappropriatenessof positioning information is configured by various filter processesperformed by the control unit 11 of the wrist terminal 1, the presentinvention is not limited thereto. In addition, determination devicescorresponding to various filters may be configured by hardware, and thewrist terminal 1 may perform the process using output results of thedetermination devices.

Furthermore, in the embodiment described above, in the loss extensionfilter process, as the acquisition status of the positioninginformation, a part (loss part) in which the positioning information isdeficient may be referred to from various viewpoints. In other words,instead of referring to a time in which positioning information is notacquired (the length of the loss time) as a loss part, the number oftimes of not acquiring positioning information or the like may bereferred to. In addition, in correspondence with this, in a case wherethe positioning information is deleted from the history data, instead ofsetting a loss extension period (time), setting of the number of timesof loss extension or the like may be performed.

In the above-described embodiment, the wrist terminal is given as anexample of an electronic device to which the present invention isapplied. However, the embodiment is not particularly limited thereto.For example, the present invention is applicable to general electronicdevices having the function of measuring exercise. As more specificexamples, the present invention is applicable to a notebook-typepersonal computer, a tablet terminal, a camcorder, a portable navigationdevice, a cell phone, a smartphone, and a portable gaming device.

In the above-described embodiment, the control unit 11 in the wristterminal 1 is controls the function shown in the flowchart of FIGS. 8 to11 and FIG. 14. Alternatively, data may be transmitted to a smartphoneand the like via the wireless communication module 21, and thesmartphone may perform arithmetic processing and return the result ofthe arithmetic processing back to the wrist terminal 1, whereby the LCD14 may display the result. In the above-described embodiment, varioustypes of data are recorded in the RAM 17 inside the wrist terminal 1 orthe removable medium 31. Alternatively, data may be transmitted throughthe wireless communication module 21 to a smartphone and may be recordedinto the smartphone, for example. That is, when the function of thewrist terminal 1 is dispersedly implemented to a plurality of electronicapparatuses, the position specifying system can be configured. In thiscase, with cooperation of each of the electronic apparatuses implementedwith various functions, the function corresponding to the wrist terminal1 performing the position specifying process can be realized.

The processing sequence described above can be executed by hardware, andcan also be executed by software. In other words, the functionalconfiguration shown in FIG. 2 is merely an illustrative example, and thepresent invention is not particularly limited thereto. Morespecifically, the types of functional blocks employed to realize theabove-described functions are not particularly limited to the exampleshown in FIG. 2, so long as the wrist terminal 1 can be provided withthe functions enabling the aforementioned processing sequence to beexecuted as a whole. A single functional block may be configured by asingle piece of hardware, a single installation of software, or anycombination thereof. The functional configurations of the presentembodiment are realized by a processor executing arithmetic processing,and processors that can be used for the present embodiment include aunit configured by a single unit of a variety of single processingdevices such as a single processor, multi-processor, multi-coreprocessor, etc., and a unit in which the variety of processing devicesare combined with a processing circuit such as ASIC (ApplicationSpecific Integrated Circuit) or FPGA (Field-Programmable Gate Array).

In the case of having the series of processing executed by software, theprogram constituting this software is installed from a network orrecording medium to a computer or the like. The computer may be acomputer embedded in dedicated hardware. In addition, the computer maybe a computer capable of executing various functions, e.g., a generalpurpose personal computer, by installing various programs.

The storage medium containing such a program can not only be constitutedby the removable medium 31 shown in FIG. 1B distributed separately fromthe device main body for supplying the program to a user, but also canbe constituted by a storage medium or the like supplied to the user in astate incorporated in the device main body in advance. The removablemedium 31 is composed of, for example, a magnetic disk (including afloppy disk), an optical disk, a magnetic optical disk, or the like. Theoptical disk is composed of, for example, a CD-ROM (Compact Disk-ReadOnly Memory), a DVD (Digital Versatile Disk), Blu-ray (RegisteredTrademark) or the like. The magnetic optical disk is composed of an MD(Mini-Disk) or the like. The storage medium supplied to the user in astate incorporated in the device main body in advance is constituted by,for example, the ROM 12 of FIG. 1 in which the program is recorded.

It should be noted that, in the present specification, the stepsdefining the program recorded in the storage medium include not only theprocessing executed in a time series following this order, but alsoprocessing executed in parallel or individually, which is notnecessarily executed in a time series.

The embodiments of the present invention described above are onlyillustrative, and are not to limit the technical scope of the presentinvention. The present invention can assume various other embodiments.Additionally, it is possible to make various modifications thereto suchas omissions or replacements within a scope not departing from thespirit of the present invention. These embodiments or modificationsthereof are within the scope and the spirit of the invention describedin the present specification, and within the scope of the inventionrecited in the claims and equivalents thereof.

What is claimed is:
 1. An electronic apparatus comprising: a processor;and a memory, wherein the processor executes a program stored in thememory to perform operations comprising: acquiring a series of positioninformation of a user; judging whether or not a loss part is present inthe series of position information acquired; and in a case where it isjudged that the loss part is present, specifying a predetermined partincluding the loss part and an adjacent part which is adjacent to theloss part, wherein the adjacent part is arranged after the loss part andhas a predetermined time length which is determined based on apredetermined ratio to the loss part, and wherein the predetermined partis a part that is not appropriate for display in the series of positioninformation.
 2. The electronic apparatus according to claim 1, whereinthe processor is further configured to output the series of positioninformation in which the predetermined part is specified.
 3. Theelectronic apparatus according to claim 2, wherein outputting the seriesof position information further comprises outputting data acquired byexcluding the predetermined part from the series of positioninformation.
 4. The electronic apparatus according to claim 3, whereinspecifying the predetermined part further comprises variably setting alength of a period in which position information subsequent to the losspart is not output.
 5. The electronic apparatus according to claim 3,wherein, as a length of the loss part increases, specifying thepredetermined part further comprises setting a length of a period inwhich position information subsequent to the loss part is not output. 6.The electronic apparatus according to claim 3, wherein in a case where alength of the loss part is equal to or longer than a threshold,specifying the predetermined part further comprises setting a period inwhich position information subsequent to the loss part is not output. 7.The electronic apparatus according to claim 3, wherein specifying thepredetermined part further comprises: discarding or invalidating theposition information acquired in a period in which the positioninformation subsequent to the loss part is not output, and maintainingthe position information acquired after elapse of the period in whichthe position information subsequent to the loss part is not output. 8.The electronic apparatus according to claim 2, wherein specifying thepredetermined part further comprises variably setting a length of aperiod in which position information subsequent to the loss part is notoutput.
 9. The electronic apparatus according to claim 8, wherein, as alength of the loss part increases, specifying the predetermined partfurther comprises setting a length of a period in which positioninformation subsequent to the loss part is not output.
 10. Theelectronic apparatus according to claim 8, wherein in a case where alength of the loss part is equal to or longer than a threshold,specifying the predetermined part further comprises setting a period inwhich position information subsequent to the loss part is not output.11. The electronic apparatus according to claim 8, wherein specifyingthe predetermined part further comprises: discarding or invalidating theposition information acquired in the period in which the positioninformation subsequent to the loss part is not output, and maintainingthe position information acquired after elapse of the period in whichthe position information subsequent to the loss part is not output. 12.The electronic apparatus according to claim 2, wherein, as a length ofthe loss part increases, specifying the predetermined part furthercomprises setting a length of a period in which position informationsubsequent to the loss part is not output.
 13. The electronic apparatusaccording to claim 12, wherein in a case where the length of the losspart is equal to or longer than a threshold, specifying thepredetermined part further comprises setting the length of the period inwhich the position information subsequent to the loss part is notoutput.
 14. The electronic apparatus according to claim 12, whereinspecifying the predetermined part further comprises: discarding orinvalidating the position information acquired in the period in whichthe position information subsequent to the loss part is not output, andmaintaining the position information acquired after elapse of the periodin which the position information subsequent to the loss part is notoutput.
 15. The electronic apparatus according to claim 2, wherein in acase where a length of the loss part is equal to or longer than athreshold, specifying the predetermined part further comprises setting aperiod in which position information subsequent to the loss part is notoutput.
 16. The electronic apparatus according to claim 15, whereinspecifying the predetermined part further comprises: discarding orinvalidating the position information acquired in the period in whichthe position information subsequent to the loss part is not output, andmaintaining the position information acquired after elapse of the periodin which the position information subsequent to the loss part is notoutput.
 17. The electronic apparatus according to claim 2, whereinspecifying the predetermined part further comprises: discarding orinvalidating the position information acquired in a period in which theposition information subsequent to the loss part is not output, andmaintaining the position information acquired after elapse of the periodin which the position information subsequent to the loss part is notoutput.
 18. A position specifying system comprising: a first electronicapparatus that includes a processor and a memory; and a secondelectronic apparatus that includes a processor and a memory, wherein inat least one of the first electronic apparatus and the second electronicapparatus, the processor executes a program stored in the memory toperform operations including: acquiring a series of position informationof a user; judging whether or not a loss part is present in the seriesof position information acquired; and in a case where it is judged thatthe loss part is present, specifying a predetermined part including theloss part and an adjacent part which is adjacent to the loss part,wherein the adjacent part is arranged after the loss part and has apredetermined time length which is determined based on a predeterminedratio to the loss part, and wherein the predetermined part is a partthat is not appropriate for display in the series of positioninformation.
 19. A position specifying method executed by a processor ofan electronic apparatus under control of a program stored in a memory,the position specifying method comprising: acquiring a series ofposition information of a user; judging whether or not a loss part ispresent in the series of position information acquired; and in a casewhere it is judged that the loss part is present, specifying apredetermined part including the loss part and an adjacent part which isadjacent to the loss part, wherein the adjacent part is arranged afterthe loss part and has a predetermined time length which is determinedbased on a predetermined ratio to the loss part, and wherein thepredetermined part is a part that is not appropriate for display in theseries of position information.
 20. A non-transitory computer-readablestorage medium storing a program that is executable by a computer thatcomprises a processor, the program being executable to cause thecomputer to perform operations comprising: acquiring a series ofposition information of a user; judging whether or not a loss part ispresent in the series of position information acquired; and in a casewhere it is judged that the loss part is present, specifying apredetermined part including the loss part and an adjacent part which isadjacent to the loss part, wherein the adjacent part is arranged afterthe loss part and has a predetermined time length which is determinedbased on a predetermined ratio to the loss part, and wherein thepredetermined part is a part that is not appropriate for display in theseries of position information.